With the rapid growth in the number of wireless applications, services and devices, using a single wireless technology such as a second generation (2G) and third gener- ation (3G) wireless system would not be efficient to deliver high speed data rate and quality-of-service (QoS) support to mobile users in a seamless way. The next genera- tion wireless systems (also sometimes referred to as Fourth generation (4G) systems) are being devised with the vision of heterogeneity in which a mobile user/device will be able to connect to multiple wireless networks (e.g., WLAN, cellular, WMAN) simultaneously.
標簽： Heterogeneous Wireless Networks Access
上傳時間： 2020-05-27
上傳用戶：shancjb
The third generation (3G) mobile communication system is the next big thing in the world of mobile telecommunications. The first generation included analog mobile phones [e.g., Total Access Communications Systems (TACS), Nordic Mobile Telephone (NMT), and Advanced Mobile Phone Service (AMPS)], and the second generation (2G) included digital mobile phones [e.g., global system for mobile communications (GSM), personal digital cellular (PDC), and digital AMPS (D-AMPS)]. The 3G will bring digital multimedia handsets with high data transmission rates, capable of providing much more than basic voice calls.
標簽： Communications Introduction Mobile 3G to
上傳時間： 2020-05-27
上傳用戶：shancjb
With the rapid growth of the wireless mobile applications, wireless voice has begun to challenge wireline voice, whereas the desire to access e-mail, surf the Web or download music (e.g., MP3) wirelessly is increasing for wireless data. While second generation (2G) cellular wireless systems, such as cdmaOne1, GSM2 and TDMA3, introduced digital technology to wireless cellular systems to deal with the increasing demand for wireless applications, there is still the need for more spectrally efficient technologies for two reasons. First, wireless voice capacity is expected to continue to grow. Second, the introduction of high-speed wireless data will require more bandwidth.
標簽： Wireless Systems Mobile Beyond and 3G
上傳時間： 2020-05-30
上傳用戶：shancjb
Wireless communications has become a field of enormous scientific and economic interest. Recent success stories include 2G and 3G cellular voice and data services (e.g., GSM and UMTS), wireless local area networks (WiFi/IEEE 802.11x), wireless broadband access (WiMAX/IEEE 802.16x), and digital broadcast systems (DVB, DAB, DRM). On the physical layer side, traditional designs typically assume that the radio channel remains constant for the duration of a data block. However, researchers and system designers are increasingly shifting their attention to channels that may vary within a block. In addition to time dispersion caused by multipath propagation, these rapidly time-varying channels feature frequency dispersion resulting from the Doppler effect. They are, thus, often referred to as being “doubly dispersive.”
標簽： Time-Varying Channels
上傳時間： 2020-06-01
上傳用戶：shancjb
The continuing explosive growth in mobile communication is demanding more spectrally efficient radio access technologies than the prevalent second generation (2G) systems such as GSM to handle just the voice traffic. We are already witnessing high levels of mobile penetration exceeding 70% in some countries. It is anticipated that by 2010 more than half of all communications will be carried out by mobile cellular networks. On the other hand, the information revolution and changing life habits are bringing the requirement of commu- nicating on a multimedia level to the mobile environment. But the data handling capabilities and flexibility of the 2G cellular systems are limited.
上傳時間： 2020-06-01
上傳用戶：shancjb
Xilinx FPGA Virtex-7 全系列（AD集成封裝庫），IntLib后綴文件，PCB封裝帶3D視圖，拆分后文件為PcbLib+SchLib格式，Altium Designer原理圖庫+PCB封裝庫，集成封裝型號列表：Library Component Count : 157Name Description----------------------------------------------------------------------------------------------------XC7V2000T-1FHG1761C Virtex-7 FPGA, 1200 User I/Os, 36 GTX, 1760-Ball BGA, Speed Grade 1, Commerical Grade, Pb-FreeXC7V2000T-1FHG1761I Virtex-7 FPGA, 1200 User I/Os, 36 GTX, 1760-Ball BGA, Speed Grade 1, Industrial Grade, Pb-FreeXC7V2000T-1FLG1925C Virtex-7 FPGA, 1200 User I/Os, 16 GTX, 1924-Ball BGA, Speed Grade 1, Commercial Grade, Pb-FreeXC7V2000T-1FLG1925I Virtex-7 FPGA, 1200 User I/Os, 16 GTX, 1924-Ball BGA, Speed Grade 1, Industrial Grade, Pb-FreeXC7V2000T-2FHG1761C Virtex-7 FPGA, 1200 User I/Os, 36 GTX, 1760-Ball BGA, Speed Grade 2, Commerical Grade, Pb-FreeXC7V2000T-2FLG1925C Virtex-7 FPGA, 1200 User I/Os, 16 GTX, 1924-Ball BGA, Speed Grade 2, Commercial Grade, Pb-FreeXC7V2000T-2GFHG1761EVirtex-7 FPGA, 1200 User I/Os, 36 GTX, 1760-Ball BGA, Speed Grade 2G, Extended Grade, Pb-FreeXC7V2000T-2GFLG1925EVirtex-7 FPGA, 1200 User I/Os, 16 GTX, 1924-Ball BGA, Speed Grade 2G, Extended Grade, Pb-FreeXC7V2000T-2LFHG1761EVirtex-7 FPGA, 1200 User I/Os, 36 GTX, 1760-Ball BGA, Speed Grade 2L, Extended Grade, Pb-FreeXC7V2000T-2LFLG1925EVirtex-7 FPGA, 1200 User I/Os, 16 GTX, 1924-Ball BGA, Speed Grade 2L, Extended Grade, Pb-FreeXC7V585T-1FFG1157C Virtex-7 FPGA, 850 User I/Os, 20 GTX, 1156-Ball BGA, Speed Grade 1, Commercial Grade, Pb-FreeXC7V585T-1FFG1157I Virtex-7 FPGA, 850 User I/Os, 20 GTX, 1156-Ball BGA, Speed Grade 1, Industrial Grade, Pb-FreeXC7V585T-1FFG1761C Virtex-7 FPGA, 850 User I/Os, 36 GTX, 1760-Ball BGA, Speed Grade 1, Commercial Grade, Pb-FreeXC7V585T-1FFG1761I Virtex-7 FPGA, 850 User I/Os, 36 GTX, 1760-Ball BGA, Speed Grade 1, Industrial Grade, Pb-FreeXC7V585T-2FFG1157C Virtex-7 FPGA, 850 User I/Os, 20 GTX, 1156-Ball BGA, Speed Grade 2, Commercial Grade, Pb-FreeXC7V
上傳時間： 2021-12-22
上傳用戶：aben
廣和通是中國首家A股上市的物聯網無線模組企業。致力于將可靠、便捷、安全、智能的無線通信解決方案普及至每一個物聯網應用場景，豐富智慧生活。廣和通提供創新的5G、4G、3G、2G、NB-IoT、LTE-M、智能、車規級無線通信模組及物聯網應用一站式無線通信解決方案 。廣和通擁有全球1000多名員工，產品及服務遍及100多個國家。
標簽： 物聯網
上傳時間： 2021-12-26
上傳用戶：
5G 底層核心技術專利現狀分析 無線通信技術從 2G 到 3G 是一個歷史性的跨越，從單純的語音通話和簡單的短信數據傳輸， 跨入了無線互聯網。 在 2009 年發放 3G 牌照的時候，產業界最希望找到的是應用無線寬帶能力的殺手級應用。 當時最早的應用是把 3G 當做無線上網卡銷售，例如中國電信的 CDMA2000 每月 300 小時不限流 量的 3G 上網卡。而通過 4 年多的產業實踐，到了 4G 時代，應用無線寬帶能力的導航、音樂、 在線視頻、購物、支付、游戲等殺手級應用已經涌現，無線寬帶的流量開始變得珍貴，目前中 國電信的 4G 套餐就沒有按小時計費全部都按流量計費。 正是看到了產業的興旺發達，在 2013 年剛剛發放 4G 牌照后，2015 年 5G 就成為了熱門的 話題。之前的分析占據 5G 產業的制高點關鍵在于底層核心技術。有一種觀點認為，目前 5G 的 框架還沒有確定，談核心空口技術是否過早。 5G 底層技術專利形成時間遠早于 5G 標準框架 目前對于 5G 的標準制定工作已經開始加速，但初步的框架確定估計也要到 2016 年。但標 準框架未定之時，正是底層技術核心專利爭奪的關鍵時期。從歷史上的經驗看。我國自主提出 的 3G 國際標準 TD-SCDMA 的標準框架專利 CN97104039.7 是在 1997 年由信威通信申請的。而高 通公司賴以掌控 3G 產業鏈命脈的底層 CDMA 核心專利卻是美國高通公司于
標簽： 5g
上傳時間： 2022-02-21
上傳用戶：
本設計以 STM32 單片機和 AD7791 實現電子秤的設計。設計采用電阻式應變片組成應變電橋的稱重傳感器采集重量的電壓信號，采用兩個零漂移放大器 ADA4528 組成了前端差分放大電路，設計采用了差分濾波器和共模濾波器，有效抑制了進入模數轉換模塊 AD7791 中的噪聲，STM32 通過 SPI 接口控制 AD7791 進行數據 A/D 轉換，讀取和數據處理，在 LCD 顯示屏顯示測量結果。經過實際測試，稱重傳感器測量范圍在 1g ～ 6KG 之間，測量范圍在 10g 內時測量誤差能達到 0.2g 之內。
上傳時間： 2022-05-07
上傳用戶：
我們代理的JeJu Semicon是韓國濟州半導體的nand flash是使用hynix 32nm晶元，封測在hynix 封測廠WINPAC進行，廠商號是HYNIX的廠商號，就絲印改成JSC型號絲印。因此與hynix nand flash只是型號不一樣,硬件軟件上都是一樣的,直接更換貼片即。目前在網絡攝像機，可視樓宇產品，考勤機，人臉識別等產品大量出貨。 JSC品牌1G：JS27HU1G08SCN-25 對應的hynix 1G 型號 H27U1G8F2CTR-BCJSC品牌2G：JS27HU2G08SCN-25 對應的hynix 2G 型號 H27U2G8F2DTR-BCJSC品牌4G：JS27HU4G08SDN-25 對應的hynix 4G 型號 H27U4G8F2ETR-BC
上傳時間： 2022-05-25
上傳用戶：
